Ingrid, a chemist, has 180 milliliters of nitric acid with a molarity of 18 and 490 milliliters of nitric acid with a molarity of 5. (Molarity is a chemical term; the larger the molarity, the more concentrated the acid.) Set up a quantity-rate table. Find the average rate (molarity) for the table by dividing the sum of the Q $\text {.}$ R column by the sum of the quantity column. Round the answer to the nearest whole number.

Question

Quizplus · Accepted Answer

First, we set up the quantity-rate table:

|      |  Quantity (mL) |  Rate (M) |
|------|----------------|-----------|
|  18 M Nitric Acid  |     180        |      18     |
|  5 M Nitric Acid   |     490         |      5       |
| Total |     670         |             |

To find the average rate, we divide the sum of the Q * R column (180*18 + 490*5 = 9540) by the sum of the quantity column (670).

Average rate = 9540/670 = 14.253

Rounded to the nearest whole number, the answer is 14, which is closest to choice D (8).

Ingrid, a Chemist, Has 180 Milliliters of Nitric Acid with a Molarity